Braun tube



Dec. 26, 1939. w, UHLMANN I BRAUN TUBE Filed Feb. 8, 1938 4 5 l Z 7 n mmuw. n n n- Hu. ad f f n 2 a a v Patented Dec. 26, 1939 l lt UNITED STATES PATENT OFFiCE BRAUN TUBE Wolfram Uhlmann, Berlin, Germany, assignor to C. .Lorenz Aktiengesellschaft, Berlin-Tempelhof, Lorenzweg, Germany, a company Application February 8, 1938, Serial No. 189,301 In Germany February 11, 1937 2 Claims. (Cl. Z50-155) The present invention relates to Braun tubes, closely described. The two members o and 6 and particularly to improvements in the system form a Wehnelt cylinder. Two insulating rings which produces the electron beam in such tubes. 8 and I0 together with an intermediate metal The individual electrodes of the cathode ray disc 9 are then placed on the top of the cap 5.

5 producing system in Braun tubes employed in The disc 9 which is provided with a central bore 5 the practice are attached to supporting rods of serves as suction electrode. The insulating ring insulating material which are arranged in paral- I in turn carries a further electrode ll likewise lel t0 the aXiS of the tube. These rods are fixed having a central hole. An electron lens cylinder to the stem of the tube in any manner and carry l2 iS plaCed dIeCtly On the tOD 0f the eleCtIOde l0 the entire electrode system. Each individual Il and is provided with a diaphragm i3. The 10 electrode is attached to the supporting rods by inner surface of a further insulating body I4 clip rings in order to prevent axial displacement serves for centering the electron lens cylinder,

thereof. It is necessary that each individual while its outer surface is adapted to centre an electrode is concentrically positioned in the anode cylinder l which encompasses the elecl5 mounting peration since the reliability of the tron lens cylinder l2. This insulating body lll 15 tube is highly dependent upon this requirement. ls provided with a shoulder forming a seat for the The structure of television tubes hitherto known anode Cylinder l5. In this State, the entire eleC- has not been well adapted for series production trode syStem iS adapted t0 he assembled t0 One since utmost accuracy and conscientiousness Structural unit. This is accomplished by Ineens must be required from each Workman in charge of clamping IOdS, egthlee thereOf-L Which are 20 of the mounting operation. It is therefore not xed to the anode cylinder l5 and extended astonishing when under such circumstances the through the lower base plate 3 where the required individual tubes of a manufacturing series pretension may be applied theletO- F01 the pLlIDOSe sent different properties. of securing accurate concentrical seat for the 5 The invention proposes quite new ways for diierent electrodes, the insulating rings are pro- 25 mounting the electrode of tubes above referred vided with a special cross sectional area, instead to. According to the invention, each electrode is 0f having their InaJ'OI Surfaces ln parallel With a circular-symmetric body and these bodies are one another. Nevertheless, alSO plane insulating mounted one upon the other by the agency of rings may be eInDlOyed, PTOVded that the edges intermediate insulating rings whereupon an axial of the electrodes are equipped with booklets. 30 tension is applied to the assembly so as to obtain The cap 5 and the tubular member 6 act as a uniform body. a Wehne-lt cylinder as mentioned above. The

Cathode ray producing systems are known actubular member is welded to the cover 5 and cording to which all electrodes are mounted in adapted to receive the cathode which comprises an insulating body of tubular shape. This body a small insulating tube i6, the upper end oi 35 is provided with shoulders onto which the elecwhich carries the metallic support for the electrodes are clamped. However, the manufacturtron emitting layer l?. This rod-shaped cathode ing of such complicated insulating members is is mounted in a member i8 of an insulating maextraordinarily diicult, whereas the present interial, or of a metal oi low thermal conductivity.

vention employs simple rings which are easily The cathode and the member E8 form one unit 40 to be produced. which is passed into the tube 6 and fixed in axial The present invention will be more readily direction. The cylindrical portion of the cap understood from the following description taken electrode 5 may be provided with one or more in conjunction with the accompanying drawing, apertures, so as to permit the correct adjustment which shows a. cross section through one emof the axial interspace between the cap and the 45 bodiment of the invention. member l'i to be observed. It is also possible A number of supporting rods 2 are xed in a to provide the body I8 with a projecting collarv ring l which is clamped around the stem A of as a seat for the cathode so as to compulsorily the tube. These supporting rods carry an annusecure the correct interspace between the face of,

so lar base plate 3 adapted to support the entire the cathode and the adjacent electrode after this 50 electrode system. A ring d of insulating matebody has been brought into position. It will be rial which is covered by a metal cap 5 is first readily understood that this arrangement rebrought into position in the base plate 3. The quires that the distance between the face of the inner surface of the cap 5 carries a tubular menicathode and the collar has been exactly dened 5;, ber 6, the function of which is hereinafter more in manufacturing the cathode, and that the tubu- 55 lar member 6 has a predetermined length. In such cases an adjustment of the cathode in the axial direction becomes superfluous. This new arrangement presents essential advantages over the known cathode structures, since the old supporting lugs for the cathode are omitted and the subsequent centering measures have been rendered superfluous.

The lead-in conductors to the individual electrodes are carried through slots in the insulating rings as far as these cannot be applied from the outer side of the structure.

What is claimed is:

1. In a Braun tube, a cathode ray producing system, comprising a rod-shaped cathode, a circular symmetric member therefor, having a shoulder, a circular control electrode, further electrodes likewise of circular symmetric shape, insulating rings adapted to separate the individual electrodes from one another and having cross sectional shapes of diierent diameters so as to provide concentrical seats therefor, means for combining said electrodes and insulating rings to one unit, and a diaphragm, said shoulder being adapted to define the interspace between the electron emitting face of the cathode and said adjacent diaphragm when the cathode and its holder are inserted in the circular control electrode.

2. A Braun tube comprising an annular ring of insulating material having a portion of reduced diameter, a metal cylindrical cap therefor containing a metal tube forming with said cap a Wehnelt cylinder, an electron emitter Within said cylinder, a plurality of electrodes superimposed on said cap and insulated therefrom and from one another by insulating rings, a tubular insulating body having internal portions of different diameters to engage respectively said cap and said electrodes, a tubular anode encircling said body and fixed to the upper end thereof and means for clamping said anode to said annular ring rst mentioned to hold all of said parts together in a single unit.

WOLFRAM UI-ILMANN. 

